Hormones and Endocrine System

﻿*the endocrine system is made up of glands that produce the secrete hormones. The image above shows the basic anatomy of endocrine system in both male and female body. The only difference between them is in the pelvis-- female has ovary while male has testes.*

Chapter summary

Concept 45.1

Hormones and other signaling molecules trigger responses by binding to specific target cells, which have receptors for a particular secreted molecule.So, Hormones act as secreted molecules in endocrine signaling. Local regulators function in paracrine and autocrine signaling. Neurotransmitters and Neurohormones act in synaptic and neuroendocrine signalings.Pheromones function in the communication of the same animal species.

The response pathways between different hormones vary. A water-soluable hormone binds to a signal receptor protein in plasma membrane. A lipid-soluable hormone binds to an intracellular signal receptor, either in the cytoplasm or nuleus. The hormone-receptor complex acts as a transcription factor.

One hormone with the same receptors but different intracellular proteins can have different effects.

* The hormone thyroxine is responsible for the resorption of the tadpole's tail as the frog develops into its adult form.*

Concept 45.2

Negative feedback,a loop in which the response reduces the initial hormone signaling stimulus, are an essential part of many hormone pathways.

Two antagonistic hormones, insulin and glucagon, regulate the concentration of glucose in the blood.Insulin lowers blood glucose levels by stimulating nearly all body cells outside the brain to take up glucose and by slowing glycogen breakdown in the liver. By contrast, Glucagon increase the blood glucose levels by coverting amino acids and glycerol to glucose and release glucose into bloodstream.

Diabetes mellitus, is a disorder caused by a decrease of insulin. Blood glucose levels rise but because of the lack of insulin, they are not able to be leveled down.

Concept 45.3

Endocrine and nervous system can coodinate in both invertebrates and verterbrates. In verterbrates, Hypothalamus travels to pituitary gland. Pituitary gland includes posterior and anterior pituitary in the brain, posterior grows downward toward the mouth while anterior grows upward toward the brain during the embryonic development.

Posterior pituitary hormones release two neurohormones, oxytocin and antidiuretic hormones(ADH), Anterior pituitary hormones secrete many different hormones and itself is regulated by hormones secreted by the hypothalamus.

(left) *The posterior pituitary gland is an extension of the hypothalamus, neurosecretory cells make oxytocin and ADH and transport them to posterior pituitary.*(right) *The hypothalamic hormones are secreted by neurosecretory cells and enter a network within the hypothalamus.Then enter a second network in the anterior pituitary. Much more products are released than in posterior pituitary gland.*

Concept 45.4

There are many types of hormones in endocrine system. Thyroid hormone controls metabolism and development. Parathyroid hormone and vitamin D controls the blood calcium. Adrenal hormones responses to stress, which includes catecholamines and steriod. Gonadal sex hormones affect growth, development and reproductive cycles.

Vocabulary

1. Hormone: one of many secreted chemicals that reansmit information between animal cells.
eg. Hormones trigger responses by binding to specific receptor proteins in or on target cells.
2. Endocrine glands:﻿ glands in endocrien system that secrete their products.eg. Other endocrine cells are grouped in ductless organs called endocrine glands.3. local regulators: secreted molecules that act over short distances and reach their target molecules by diffusion.eg. Local regulators function in paracrine and autocrine signaling.
4. Neurotansmitters: neurons secrete molecules that diffuse a very short distance to bind receptors on the target cells.
eg. Neurotransmitters are central to sensation, memory, cognition and movement.
5. Neutohormones: molecules travel through the bloodstream to reach target cells.
eg. These molecules, which travel though the bloodstream to reach target cells are called neutohormones.
6. Negative feedback: a loop in which the response reduces the initial stimulus.
eg. Negative feedback regulation prevents excessive pathway activity.
7. Pituitay gland: a gland located at its base.
eg. The pituitary gland has discrete posterior and anterior parts.
8. Posterior pituitray: or neurohypophysis, is an extension of the hypothalamus that grows downward toward the mouth.
eg. The posterior pituitary stores and secretes two hormones made by the hypothalamus.
9. Anterior pituitary: or adenohypophysis, is a tissue that grows upward toward the brain.
eg. Hormones released by the hypothalamus regulate secretion of hormones by the anterior pituitary.
10. Tropic hormone: a hormone that regulates the function of endocrine glands or cells.
eg. TSH is an example of tropic hormone.
11. Thyroid gland: one of the largest gland in endocrine system.
eg. The thyroid gland consists of two lobes on the ventral surface of the trachea.
12. parathyriod gland: a set of four small structures embeddded in the posterior surface of the thyroid.
eg. The parathyriod gland plays a major role in blood regulation.
13. adrenal glands: glands that sit astop the kidney.
eg. The adrenal glands of vertebrates are in each case associated with the kidneys.
14. pineal gland: a small mass of tissue near the center of the mammalian brain.
eg. The pineal gland synthesizes and secretes the hormone melatonin.
15. signal transduction: changes in cellular proteins that converts the extracellular chemical signal to a specific intracellular response.
eg. A signal transduction pathway typically involves mutiple steps, each involving specific molecular interactions.
16. hypothalamus: A portion of brain that contains a number of small nuclei.
eg. In vertebrates, the hypothalamus plays a central role in integrating the endocrine and nervous system.
17. Growth hormone(GH):A protein-based peptide hormone that stimulates growth.
eg. Growth hormone stimulates growth through tropic and nontropic effects.

Images:

(left) *Steriod hormone receptors are located in the cytosol, it directly regulate gene expression. Hormone binds to the receptor in cytosol and the hormone-receptor complex binds to DNA to change the gene activity.*

(right) *Water-soluble hormones bind to the receptor in plasma membrane, this interaction triggers the change in gene transcription in the nucleus, turning glycogen into glucose.**Insulin and glucagon hormones regulate the concentration of glucose in the blood. As shown in the image, insulin stimulates glycogen formation and body cells to take up glucose from the blood.Also, in the liver, insulin slow glycogen breakdown to decrease the glucose levels. By contrast, glycagon stimulates glycogen breakdown and converts glycogen into glucose in the liver. Thus, the normal blood glucose level is formed.*

(left) * secretin signaling shown above is an example of a simple endocrine pathway. The hormone binds to its target cells and results in a specific response. This response reduces the initial stimulus, so it involves negative feedback.*
(right) *In this example, stimulus causes hypothalamus to send a nerve impulse to the posterior pituitary, which is responsed by neurosecretroy cell. The neurohormone binds to the target cells and result in a specific response.The response increasest the initial stimulus, so it involves positive feedback.*

*As we all know, stress can cause hormone to activate. Different terms of stress causes different responses. For short-term
stress, the adrenal medulla via nerve impulse. For long-term stress, the adrenal cortex cia hormonal signals through bloodstream. The different responses are shown above.*
*The diagram above shows the evolution of adult butterfly, The brain give larva and pupa JH, assisting the growth,*

Animation and video clips:

This animation is very easy to understand and can help you a lot as well. It gives the basic anatomy of endocrine system and the function of different hormones. It involves some basic knowledge about endocrine system you need to know.*

online lessons:

*This video clip is provided by a biological professor. It basically gives us a closer look of this chapter and somehow like an online class. He also took surveys about the major glands and hormones in human body. The way to summary the chapter is a way easier than just reading the chapter by yourself.*

Brief Review:Your endocrine system is a complex network composed of hormone-producing glands, such as the hypothalamus, pituitary and anterior glands,thyroid, and organs, such as liver, pancreas and kidneys. It maintain different hormones to balance and control a number of functions throughout the body. The main purpose of endocrine system is extracellular communication.

Different hormones binds to different receptors and vary in functions, such as water-soluble and lipid-soluble hormone receptors are either in plasma membrane or nucleus.

Quizes and study guide:

News stories:

High levels of PFCs might bring early Menopause

HealthDay news image

WEDNESDAY, March 23 (HealthDay News) -- Women with higher levels of certain chemicals used in many household products have lower levels of estrogen and are more likely to experience early menopause, a new study finds.

Researchers looked at perfluorocarbons (PFCs), which are endocrine-disrupting chemicals found in products such as toys, clothing, furniture, carpets, paints and plastic food containers. This new study of 25,957 women, aged 18 to 65, found an association between PFC exposure, decreased levels of the female sex hormone estradiol, and early menopause in women over age 42.

The findings appear in the Journal of Clinical Endocrinology & Metabolism.
The widespread use of PFCs has led to their presence in water, air, soil, plants, animals and humans. One study found that 98 percent of American adults have measurable concentrations of PFCs, according to background material in the study.
"There is no doubt that there is an association between exposure to PFCs and onset of menopause, but the causality is unclear," study author Sarah Knox, of West Virginia University School of Medicine, said in a journal news release. "Part of the explanation could be that women in these age groups have higher PFC levels because they are no longer losing PFCs with menstrual blood anymore, but it is still clinically disturbing because it would imply that increased PFC exposure is the natural result of menopause."
It's known that PFCs have a number of harmful effects, including increased cardiovascular risk and immune system impairment.
"Our findings suggest that PFCs are associated with endocrine disruption in women and that further research on mechanisms is warranted," Knox said.
SOURCE: Journal of Clinical Endocrinology & Metabolism, news release, March 23, 2011
HealthDay

Workshop will show ways to reduce enviromental toxins

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Lake Fong/Post-GazettePennsylvania Resources Council's environmental education coordinator Sarah Alessio Shea shows the nontoxic green cleaning kit that will be distributed to attendees of Tuesday's Healthy Body, Healthy Home, Healthy Planet Workshop being held at CCI Center on the South Side
Read more: http://www.post-gazette.com/pg/11071/1131405-114.stm#ixzz1MSStmyY0Cancer, endocrine system disruptions, allergic reactions, asthma. Those are the kinds of health problems that chemicals, toxins and carcinogens to which we're exposed in the environment can cause.
Some of those exposures can be reduced by simple changes in lifestyle; others must be changed by civic or political action.
Sarah Alessio Shea, environmental education coordinator for the Pennsylvania Resources Council, will talk about the former in a Healthy Body, Healthy Home, Healthy Planet Workshop on Tuesday from 6:30 to 8 p.m. in the CCI Center, 64 S. 14th St., South Side. Her partner for the workshop is the Center for Environmental Oncology at the University of Pittsburgh Cancer Institute, which supplies the scientific information.
Maryann Donovan, interim director of the center at Pitt, recently spoke about the health hazards for which chemicals, toxins and carcinogens may increase risk. They range from the endocrine system disruptions caused by the chemicals found in fragrances and common pesticides, to melanoma, or skin cancer, believed to be caused by exposure to UV radiation from tanning beds and the sun, to the carcinogens and nicotine inhaled during hookah smoking.
"Hookah tobacco is very toxic," she said, citing a Pitt study. "One bowl is like smoking 100 cigarettes in terms of carcinogens and nicotine."

Hyperthyroidism Top Natural Supplements for Treatment

Hyperthyroidism, the overactive functioning of the thyroid gland, results in the overproduction of the thyroid hormones (thyroxine or triiodothyronine) and causes thyrotoxicosis, a clinical disease of increased thyroid hormone presence in the blood.

A natural treatment for hyperthyroidism may include a number of herbs and traditional therapies, some of which are mentioned below:

Ginseng is one of the best treatments for hyperthyroidism. Siberian ginseng or Eleuthero is a natural supplement that helps maintain good health. It is beneficial for balancing adrenal problems as well as chronic stress.

Bugleweed is another good natural treatment; it helps deal with heart palpitations and anxiety.

Iodine is a highly essential nutrient in the treatment of hyperthyroidism. Daily dosage of vitamin D may also help promote the immune system and provide relief from a number of immune system related symptoms.

A selenium deficiency may lead to hyperthyroidism. The main source of this essential element is Brazil nuts, which can help boost the body’s immunity.

A number of deficiencies caused by hyperthyroidism may be naturally treated with magnesium in small doses, either in the form of pills or in foods such as raw seeds.

A good quantity of omega-3 fatty acids may balance the endocrine system and the thyroid hormone level in the blood, leading to a reduction in thyrotoxicosis and related conditions